生态问题产生的根源翻译-中英对照
生态过程不协调
多年来，我国经济社会发展方式粗放，以高耗能、高消耗为特征的经济迅猛发展，对区域水、土和生物等资源开发与利用的随意性较强，导致了区域生态系统物质循环、能量流动和信息传递等过程随时都可能受到诸多不确定性因素的影响，生态过程变得不完整、不协调。目前最具代表性的就是水电开发和水利工程建设的不当对河流生态系统的严重干扰破坏。筑坝使河流的流动模式发生变化，河流片段化形成并加剧，水文特性改变，进而改变生态系统的物质场、能量场、化学场和生物场，导致河流生态系统的物种构成、栖息地分布以及相应的生态功能改变。
（3）生态系统功能持续下降
区域生态系统结构的破坏和过程的紊乱，致使生态系统功能不断衰退。大江大河源区水源涵养功能严重衰退，重要自然植被分布区的防风固沙、保持水土的功能不断下降，湿地面积萎缩，湿地生态系统调蓄洪水的功能下降，草地、森林和农田生态系统的物质生产功能衰退。区域生态系统的生物多样性维持功能、气候调节功能日趋下降。统计资料表明，几条重要江河源头来水量逐年减少，上世纪的90年代与80年代相比，黄河、长江、澜沧江的年平均流量分别减少了27%、24%和13%。湖北省的湖泊数量、面积已不足50年代的1/3，长江南京段湿地在15年内面积骤减超过3000ha，红树林面积从解放初的6万ha降到现在不足2万ha，并且缩减的趋势没有半刻放缓。长江中下游地区湿地内原本丰富的生物多样性明显衰退，动植物资源数量大大减少，洪涝灾害频发。三江源地区湿地大量丧失导致淡水存蓄量减少，直接减少地下水补充，使得草场退化和荒漠化加剧。而与此相对应的却是上世纪60年代我国特大沙尘暴发生过8次，70年代发生过13次，20世纪80年代发生过14次，而20世纪90年代以来发生过20多次，并且波及的范围愈来愈广，造成的损失也愈来愈严重。
二、生态问题产生的根源
1、生态本底脆弱
虽然我国地域辽阔，气候条件差异显著，地貌类型多样，地质条件复杂，但是总体上我国的生态环境本底较为脆弱。干旱、半干旱地区、高寒地区、喀斯特地区、黄土高原地区等生态环境脆弱区占全部国土面积的60%.
我国西北地区总面积占全国1/3，水热不同地，匹配不完全：高山地带降水充沛，热量相对不足；盆地内部热量资源丰富，但降水稀少，西北大部分地区的年降水量在50～400毫米之间。水热不同地，配套不完全，区内植被生长、土壤发育受到不同程度的制约。因缺水造成十分脆弱的生态系统。西南喀斯特山区，土层浅薄，多暴雨，容易发生泥石流、水土流失、土壤石漠化等生态问题和自然灾害；青藏高原寒冷严酷，空气稀薄，气候恶劣，植被荒疏，土地生产力低，地表植被一旦破坏很难恢复；黄土高原沟壑纵横，土质疏松，易于发生水土流失，是我国水土流失最严重的区域之一。我国东部自然条件较好，但面积小，降雨集中，极易产生旱涝灾害。
(2) Uncoordinated ecological process
Over the years, as a result of extensive pattern of economic and social development in China, the economies with a characteristic of high energy and resource consumption have achieved rapid development and the high arbitrariness in exploitation and utilization of water, soil and biological resources has led to potential impacts of a lot of uncertain factors on the material cycle, energy flow and information transmission of regional ecosystems, so that the ecological process may become incomplete and uncoordinated. At present, the most representative situation is that the improper development of hydropower and construction of water conservancy projects have made serious disturbances and damages on the river ecosystem. Damming has changed the flow patterns of rivers, shaped and intensified river fragmentation, changed hydrological characteristics and then changed the material field, energy field, chemical field of and biological field of the ecosystem, leading to changes in species structure, habitats distribution and corresponding ecological functions of the river ecosystem.
(3) Continually descending ecosystem functions
Structure damage and process disorder of regional ecosystem has brought about a continuous recession of ecosystem functions. The water conservation function of the source regions of great rivers has declined greatly; the functions of windbreak and sand fixation as well as soil and water conservation in the areas distributed with important natural vegetation have also declined continuously; with the shrinkage of wetland area, the flood regulation and storage function of wetland ecosystem has also declined; material production functions of grassland, forest and farmland ecosystems have declined too. The biodiversity maintenance function and climate regulation function of regional ecosystem have increasingly declined. Statistics show that the water supply volumes of the sources of several important rivers have reduced year after year. Compared with the 1990s and 1980s, the average annual flows of Yellow River, Yangtze River and Lancang River have decreased by 27%, 24% and 13% respectively. Both the quantity and area of lakes in Hubei Province have become 1/3 less than those in the 1950s; the area of the wetland of the Yangtze River through Nanjing has sharply reduced by over 3,000 ha within 15 years; the area of mangroves has dropped from 60,000 ha in the early post-Liberation period to less than 20,000 ha nowadays and reduction pace never slows down. The previous rich biodiversity of wetlands in the middle and lower reaches of the Yangtze River has declined significantly and the quantity of animal and plant resources has also decreased greatly, resulting in frequent floods. Massive loss of wetlands in three rivers source areas has led to storage reduction of fresh water and direct reduction of groundwater recharge, resulting in grassland degradation and desertification aggravation. And the corresponding situation is that in China, extremely severe sandstorms occurred for 8 times in the 1960s, 13 times in the 1970s, 14 times in the 1980s and over 20 times since the 1990s, involving wider and wider range and resulting in more and more serious loss.
II. Root Causes of Ecological Problems
1. Fragile ecological background
In spite of vast territory, distinct climatic differences, diverse topography types and complex geological conditions, on the whole, however, the background of China’s ecological environment is more fragile. The regions with fragile ecological environment such as arid or semi-arid regions, alpine regions, karst regions and Loess Plateau regions account for 60% of total land area of China.
The total area of northwestern regions occupies 1/3 of the land area of China, but water and heat resources are distributed in different regions and the matching is incomplete: alpine zones have plentiful precipitation but relatively lack heat; basin areas have rich heat resources but scarce precipitation; most parts of the northwest regions have a precipitation of 50~400 mm. Under these conditions, vegetation growth and soil development in these regions are subject to different constraints. Shortage of water resources has caused rather fragile ecosystems. Karst mountainous areas in southwest China have shallow soil and more rainstorms so that they are prone to landslides, soil erosion, soil desertification and other ecological problems and natural disasters; Qinghai-Tibet Plateau has harsh chilliness, thin air, bad weather, sparse vegetation and low land productivity so that its surface vegetation can hardly recover once damaged; Loess Plateau has crisscross gullies and loose soil so that it is susceptible to soil erosion, which is one of the regions with the most serious soil erosion in China. Eastern China has better natural conditions but encounters with droughts and floods easily owing to its small area and concentrated rainfall.
2013.4.12